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tesseract/dict/stopper.cpp
joregan edf7e7694c silence more useless warnings 
git-svn-id: https://tesseract-ocr.googlecode.com/svn/trunk@432 d0cd1f9f-072b-0410-8dd7-cf729c803f20
2010-07-21 15:11:19 +00:00

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/******************************************************************************
** Filename: stopper.c
** Purpose: Stopping criteria for word classifier.
** Author: Dan Johnson
** History: Mon Apr 29 14:56:49 1991, DSJ, Created.
**
** (c) Copyright Hewlett-Packard Company, 1988.
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
** http://www.apache.org/licenses/LICENSE-2.0
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
******************************************************************************/
/**----------------------------------------------------------------------------
Include Files and Type Defines
----------------------------------------------------------------------------**/
#include "stopper.h"
#include "emalloc.h"
#include "matchdefs.h"
#include "callcpp.h"
#include "permute.h"
#include "context.h"
#include "danerror.h"
#include "const.h"
#include "freelist.h"
#include "efio.h"
#include "scanutils.h"
#include "unichar.h"
#include "varable.h"
#include "dict.h"
#include "image.h"
#include "ccutil.h"
#include "ratngs.h"
#include "ambigs.h"
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#ifdef __UNIX__
#include <assert.h>
#endif
#ifdef _MSC_VER
#pragma warning(disable:4244) // Conversion warnings
#pragma warning(disable:4800) // int/bool warnings
#endif
/* these are kludges - add appropriate .h file later */
/* from adaptmatch.cpp */
#define MAX_WERD_SIZE 100
typedef struct
{
VIABLE_CHOICE Choice;
float ChunkCertainty[MAX_NUM_CHUNKS];
UNICHAR_ID ChunkClass[MAX_NUM_CHUNKS];
} EXPANDED_CHOICE;
/**----------------------------------------------------------------------------
Macros
----------------------------------------------------------------------------**/
#define BestCertainty(Choices) (((VIABLE_CHOICE) first_node (Choices))->Certainty)
#define BestRating(Choices) (((VIABLE_CHOICE) first_node (Choices))->Rating)
#define BestFactor(Choices) (((VIABLE_CHOICE) first_node (Choices))->AdjustFactor)
#define AmbigThreshold(F1,F2) (((F2) - (F1)) * stopper_ambiguity_threshold_gain - \
stopper_ambiguity_threshold_offset)
/*---------------------------------------------------------------------------
Private Function Prototoypes
----------------------------------------------------------------------------*/
void AddNewChunk(VIABLE_CHOICE Choice, int Blob);
int CmpChoiceRatings(void *arg1, //VIABLE_CHOICE Choice1,
void *arg2); //VIABLE_CHOICE Choice2);
void ExpandChoice(VIABLE_CHOICE Choice, EXPANDED_CHOICE *ExpandedChoice);
int FreeBadChoice(void *item1, //VIABLE_CHOICE Choice,
void *item2); //EXPANDED_CHOICE *BestChoice);
int UniformCertainties(const BLOB_CHOICE_LIST_VECTOR &Choices,
const WERD_CHOICE &BestChoice);
/**----------------------------------------------------------------------
V a r i a b l e s
----------------------------------------------------------------------**/
double_VAR(certainty_scale, 20.0, "Certainty scaling factor");
double_VAR(stopper_nondict_certainty_base, -2.50,
"Certainty threshold for non-dict words");
double_VAR(stopper_phase2_certainty_rejection_offset, 1.0,
"Reject certainty offset");
INT_VAR(stopper_smallword_size, 2,
"Size of dict word to be treated as non-dict word");
double_VAR(stopper_certainty_per_char, -0.50,
"Certainty to add for each dict char above small word size.");
double_VAR(stopper_allowable_character_badness, 3.0,
"Max certaintly variation allowed in a word (in sigma)");
INT_VAR(stopper_debug_level, 0, "Stopper debug level");
double_VAR(stopper_ambiguity_threshold_gain, 8.0,
"Gain factor for ambiguity threshold");
double_VAR(stopper_ambiguity_threshold_offset, 1.5,
"Certainty offset for ambiguity threshold");
BOOL_VAR(stopper_no_acceptable_choices, false,
"Make AcceptableChoice() always return false. Useful"
" when there is a need to explore all segmentations");
BOOL_VAR(save_raw_choices, false, "Save all explored raw choices");
INT_VAR (tessedit_truncate_wordchoice_log, 10, "Max words to keep in list");
STRING_VAR(word_to_debug, "", "Word for which stopper debug information"
" should be printed to stdout");
STRING_VAR(word_to_debug_lengths, "", "Lengths of unichars in word_to_debug");
/**----------------------------------------------------------------------------
Public Code
----------------------------------------------------------------------------**/
/*---------------------------------------------------------------------------*/
namespace tesseract {
int Dict::AcceptableChoice(BLOB_CHOICE_LIST_VECTOR *Choices,
WERD_CHOICE *BestChoice,
const WERD_CHOICE &RawChoice,
DANGERR *fixpt,
ACCEPTABLE_CHOICE_CALLER caller,
bool *modified_blobs) {
/*
** Parameters:
** Choices choices for current segmentation
** BestChoice best choice for current segmentation
** RawChoice best raw choice for current segmentation
** Variables Used:
** stopper_nondict_certainty_base certainty for a non-dict word
** stopper_smallword_size size of word to be treated as non-word
** stopper_certainty_per_char certainty to add for each dict char
** Operation: Return TRUE if the results from this segmentation are
** good enough to stop. Otherwise return FALSE.
** Return: TRUE or FALSE.
** Exceptions: none
** History: Mon Apr 29 14:57:32 1991, DSJ, Created.
*/
float CertaintyThreshold = stopper_nondict_certainty_base;
int WordSize;
if (stopper_no_acceptable_choices) return false;
if (fixpt != NULL)
fixpt->index = -1;
if (BestChoice->length() == 0)
return (FALSE);
if (caller == CHOPPER_CALLER && BestChoice->fragment_mark()) {
if (stopper_debug_level >= 1) {
cprintf("AcceptableChoice(): a choice with fragments beats BestChoice");
}
return false;
}
bool no_dang_ambigs =
NoDangerousAmbig(BestChoice, fixpt, true, Choices, modified_blobs);
if (stopper_debug_level >= 1)
tprintf("\nStopper: %s (word=%c, case=%c)\n",
BestChoice->debug_string(getUnicharset()).string(),
(valid_word(*BestChoice) ? 'y' : 'n'),
(Context::case_ok(*BestChoice, getUnicharset()) ? 'y' : 'n'));
if (valid_word(*BestChoice) &&
Context::case_ok(*BestChoice, getUnicharset())) {
WordSize = LengthOfShortestAlphaRun(*BestChoice);
WordSize -= stopper_smallword_size;
if (WordSize < 0)
WordSize = 0;
CertaintyThreshold += WordSize * stopper_certainty_per_char;
}
if (stopper_debug_level >= 1)
tprintf("Stopper: Certainty = %4.1f, Threshold = %4.1f\n",
BestChoice->certainty(), CertaintyThreshold);
if (no_dang_ambigs &&
BestChoice->certainty() > CertaintyThreshold &&
UniformCertainties(*Choices, *BestChoice)) {
return (TRUE);
} else {
return (FALSE);
}
} /* AcceptableChoice */
/*---------------------------------------------------------------------------*/
int Dict::AcceptableResult(const WERD_CHOICE &BestChoice,
const WERD_CHOICE &RawChoice) {
/*
** Parameters:
** BestChoice best choice for current word
** RawChoice best raw choice for current word
** Variables Used:
** stopper_nondict_certainty_base certainty for a non-dict word
** stopper_smallword_size size of word to be treated as non-word
** stopper_certainty_per_char certainty to add for each dict char
** best_choices_ list of all good choices found
** reject_offset_ allowed offset before a word is rejected
** Operation: Return FALSE if the best choice for the current word
** is questionable and should be tried again on the second
** pass or should be flagged to the user.
** Return: TRUE or FALSE.
** Exceptions: none
** History: Thu May 9 14:05:05 1991, DSJ, Created.
*/
float CertaintyThreshold = stopper_nondict_certainty_base - reject_offset_;
int WordSize;
if (stopper_debug_level >= 1) {
tprintf("\nRejecter: %s (word=%c, case=%c, unambig=%c)\n",
BestChoice.debug_string(getUnicharset()).string(),
(valid_word(BestChoice) ? 'y' : 'n'),
(Context::case_ok(BestChoice, getUnicharset()) ? 'y' : 'n'),
((rest (best_choices_) != NIL) ? 'n' : 'y'));
}
if (BestChoice.length() == 0 || CurrentWordAmbig())
return (FALSE);
if (BestChoice.fragment_mark()) {
if (stopper_debug_level >= 1) {
cprintf("AcceptableResult(): a choice with fragments beats BestChoice\n");
}
return false;
}
if (valid_word(BestChoice) &&
Context::case_ok(BestChoice, getUnicharset())) {
WordSize = LengthOfShortestAlphaRun(BestChoice);
WordSize -= stopper_smallword_size;
if (WordSize < 0)
WordSize = 0;
CertaintyThreshold += WordSize * stopper_certainty_per_char;
}
if (stopper_debug_level >= 1)
cprintf ("Rejecter: Certainty = %4.1f, Threshold = %4.1f ",
BestChoice.certainty(), CertaintyThreshold);
if (BestChoice.certainty() > CertaintyThreshold &&
!stopper_no_acceptable_choices) {
if (stopper_debug_level >= 1)
cprintf("ACCEPTED\n");
return (TRUE);
}
else {
if (stopper_debug_level >= 1)
cprintf("REJECTED\n");
return (FALSE);
}
} /* AcceptableResult */
/*---------------------------------------------------------------------------*/
int Dict::AlternativeChoicesWorseThan(FLOAT32 Threshold) {
/*
** Parameters:
** Threshold minimum adjust factor for alternative choices
** Variables Used:
** best_choices_ alternative choices for current word
** Operation: This routine returns TRUE if there are no alternative
** choices for the current word OR if all alternatives have
** an adjust factor worse than Threshold.
** Return: TRUE or FALSE.
** Exceptions: none
** History: Mon Jun 3 09:36:31 1991, DSJ, Created.
*/
LIST Alternatives;
VIABLE_CHOICE Choice;
Alternatives = rest (best_choices_);
iterate(Alternatives) {
Choice = (VIABLE_CHOICE) first_node (Alternatives);
if (Choice->AdjustFactor <= Threshold)
return (FALSE);
}
return (TRUE);
} /* AlternativeChoicesWorseThan */
/*---------------------------------------------------------------------------*/
int Dict::CurrentBestChoiceIs(const WERD_CHOICE &WordChoice) {
/*
** Parameters:
** Word word that will be compared to the best choice
** Variables Used:
** best_choices_ set of best choices for current word
** Operation: Returns TRUE if Word is the same as the current best
** choice, FALSE otherwise.
** Return: TRUE or FALSE
** Exceptions: none
** History: Thu May 30 14:44:22 1991, DSJ, Created.
*/
return (best_choices_ != NIL &&
StringSameAs(WordChoice, (VIABLE_CHOICE)first_node(best_choices_)));
} /* CurrentBestChoiceIs */
/*---------------------------------------------------------------------------*/
FLOAT32 Dict::CurrentBestChoiceAdjustFactor() {
/*
** Parameters: none
** Variables Used:
** best_choices_ set of best choices for current word
** Operation: Return the adjustment factor for the best choice for
** the current word.
** Return: Adjust factor for current best choice.
** Exceptions: none
** History: Thu May 30 14:48:24 1991, DSJ, Created.
*/
VIABLE_CHOICE BestChoice;
if (best_choices_ == NIL)
return (MAX_FLOAT32);
BestChoice = (VIABLE_CHOICE) first_node (best_choices_);
return (BestChoice->AdjustFactor);
} /* CurrentBestChoiceAdjustFactor */
/*---------------------------------------------------------------------------*/
int Dict::CurrentWordAmbig() {
/*
** Parameters: none
** Variables Used:
** best_choices_ set of best choices for current word
** Operation: This routine returns TRUE if there are multiple good
** choices for the current word and FALSE otherwise.
** Return: TRUE or FALSE
** Exceptions: none
** History: Wed May 22 15:38:38 1991, DSJ, Created.
*/
return (rest (best_choices_) != NIL);
} /* CurrentWordAmbig */
/*---------------------------------------------------------------------------*/
void Dict::DebugWordChoices() {
/*
** Parameters: none
** Variables Used:
** best_raw_choice_
** best_choices_
** Operation: Print the current choices for this word to stdout.
** Return: none
** Exceptions: none
** History: Wed May 15 13:52:08 1991, DSJ, Created.
*/
LIST Choices;
int i;
char LabelString[80];
VIABLE_CHOICE VChoice = (VIABLE_CHOICE)first_node(best_choices_);
bool force_debug =
fragments_debug && VChoice != NULL && VChoice->ComposedFromCharFragments;
if (stopper_debug_level >= 1 || force_debug ||
(((STRING)word_to_debug).length() > 0 && best_choices_ &&
StringSameAs(word_to_debug.string(), word_to_debug_lengths.string(),
(VIABLE_CHOICE)first_node(best_choices_)))) {
if (best_raw_choice_)
PrintViableChoice(stderr, "\nBest Raw Choice: ", best_raw_choice_);
i = 1;
Choices = best_choices_;
if (Choices)
cprintf("\nBest Cooked Choices:\n");
iterate(Choices) {
sprintf(LabelString, "Cooked Choice #%d: ", i);
PrintViableChoice(stderr, LabelString,
(VIABLE_CHOICE)first_node(Choices));
i++;
}
}
} /* DebugWordChoices */
// Print all the choices in raw_choices_ list for non 1-1 ambiguities.
void Dict::PrintAmbigAlternatives(FILE *file, const char *label,
int label_num_unichars) {
iterate(raw_choices_) {
VIABLE_CHOICE Choice = (VIABLE_CHOICE)first_node(raw_choices_);
if (Choice->Length > 0 &&
(label_num_unichars > 1 || Choice->Length > 1)) {
for (int i = 0; i < Choice->Length; i++) {
fprintf(file, "%s",
getUnicharset().id_to_unichar(Choice->Blob[i].Class));
}
fflush(file);
fprintf(file, "\t%s\t%.4f\t%.4f\n", label,
Choice->Rating, Choice->Certainty);
}
}
}
/*---------------------------------------------------------------------------*/
void Dict::FilterWordChoices() {
/*
** Parameters: none
** Variables Used:
** best_choices_ set of choices for current word
** Operation: This routine removes from best_choices_ all choices which
** are not within a reasonable range of the best choice.
** Return: none
** Exceptions: none
** History: Wed May 15 13:08:24 1991, DSJ, Created.
*/
EXPANDED_CHOICE BestChoice;
if (best_choices_ == NIL || second_node (best_choices_) == NIL)
return;
/* compute certainties and class for each chunk in best choice */
ExpandChoice((VIABLE_CHOICE_STRUCT *)first_node(best_choices_), &BestChoice);
set_rest (best_choices_, delete_d (rest (best_choices_),
&BestChoice, FreeBadChoice));
} /* FilterWordChoices */
/*---------------------------------------------------------------------------*/
void Dict::FindClassifierErrors(FLOAT32 MinRating,
FLOAT32 MaxRating,
FLOAT32 RatingMargin,
FLOAT32 Thresholds[]) {
/*
** Parameters:
** MinRating limits how tight to make a template
** MaxRating limits how loose to make a template
** RatingMargin amount of margin to put in template
** Thresholds[] place to put error thresholds
** Operation: This routine compares the best choice for the current
** word to the best raw choice to determine which characters
** were classified incorrectly by the classifier. It then
** places a separate threshold into Thresholds for each
** character in the word. If the classifier was correct,
** MaxRating is placed into Thresholds. If the
** classifier was incorrect, the avg. match rating (error
** percentage) of the classifier's incorrect choice minus
** some margin is
** placed into thresholds. This can then be used by the
** caller to try to create a new template for the desired
** class that will classify the character with a rating better
** than the threshold value. The match rating placed into
** Thresholds is never allowed to be below MinRating in order
** to prevent trying to make overly tight templates.
** Return: none (results are placed in Thresholds)
** Exceptions: none
** History: Fri May 31 16:02:57 1991, DSJ, Created.
*/
EXPANDED_CHOICE BestRaw;
VIABLE_CHOICE Choice;
int i, j, Chunk;
FLOAT32 AvgRating;
int NumErrorChunks;
assert (best_choices_ != NIL);
assert (best_raw_choice_ != NULL);
ExpandChoice(best_raw_choice_, &BestRaw);
Choice = (VIABLE_CHOICE) first_node (best_choices_);
for (i = 0, Chunk = 0; i < Choice->Length; i++, Thresholds++) {
AvgRating = 0.0;
NumErrorChunks = 0;
for (j = 0; j < Choice->Blob[i].NumChunks; j++, Chunk++) {
if (Choice->Blob[i].Class != BestRaw.ChunkClass[Chunk]) {
AvgRating += BestRaw.ChunkCertainty[Chunk];
NumErrorChunks++;
}
}
if (NumErrorChunks > 0) {
AvgRating /= NumErrorChunks;
*Thresholds = (AvgRating / -certainty_scale) * (1.0 - RatingMargin);
}
else
*Thresholds = MaxRating;
if (*Thresholds > MaxRating)
*Thresholds = MaxRating;
if (*Thresholds < MinRating)
*Thresholds = MinRating;
}
} /* FindClassifierErrors */
/*---------------------------------------------------------------------------*/
void Dict::InitChoiceAccum() {
/*
** Parameters: none
** Operation: This routine initializes the data structures used to
** keep track the good word choices found for a word.
** Return: none
** Exceptions: none
** History: Fri May 17 07:59:00 1991, DSJ, Created.
*/
BLOB_WIDTH *BlobWidth, *End;
if (best_raw_choice_)
memfree(best_raw_choice_);
best_raw_choice_ = NULL;
if (best_choices_)
destroy_nodes(best_choices_, memfree);
best_choices_ = NIL;
if (raw_choices_)
destroy_nodes(raw_choices_, memfree);
raw_choices_ = NIL;
EnableChoiceAccum();
for (BlobWidth = current_segmentation_,
End = current_segmentation_ + MAX_NUM_CHUNKS;
BlobWidth < End; *BlobWidth++ = 1);
} /* InitChoiceAccum */
/*---------------------------------------------------------------------------*/
void Dict::LogNewSegmentation(PIECES_STATE BlobWidth) {
/*
** Parameters:
** BlobWidth[] number of chunks in each blob in segmentation
** Variables Used:
** current_segmentation blob widths for current segmentation
** Operation: This routine updates the blob widths in current_segmentation
** to be the same as provided in BlobWidth.
** Return: none
** Exceptions: none
** History: Mon May 20 11:52:26 1991, DSJ, Created.
*/
BLOB_WIDTH *Segmentation;
for (Segmentation = current_segmentation_; *BlobWidth != 0;
BlobWidth++, Segmentation++)
*Segmentation = *BlobWidth;
*Segmentation = 0;
} /* LogNewSegmentation */
/*---------------------------------------------------------------------------*/
void Dict::LogNewSplit(int Blob) {
/*
** Parameters:
** Blob index of blob that was split
** Variables Used:
** best_raw_choice_ current best raw choice
** best_choices_ list of best choices found so far
** Operation: This routine adds 1 chunk to the specified blob for each
** choice in best_choices_ and for the best_raw_choice_.
** Return: none
** Exceptions: none
** History: Mon May 20 11:38:56 1991, DSJ, Created.
*/
LIST Choices;
if (best_raw_choice_) {
AddNewChunk(best_raw_choice_, Blob);
}
Choices = best_choices_;
iterate(Choices) {
AddNewChunk ((VIABLE_CHOICE) first_node (Choices), Blob);
}
Choices = raw_choices_;
iterate(Choices) {
AddNewChunk ((VIABLE_CHOICE) first_node (Choices), Blob);
}
} /* LogNewSplit */
/*---------------------------------------------------------------------------*/
void Dict::LogNewChoice(const WERD_CHOICE &WordChoice,
FLOAT32 AdjustFactor,
const float Certainties[],
bool raw_choice) {
/*
** Parameters:
** Choice new choice for current word
** AdjustFactor adjustment factor which was applied to choice
** Certainties certainties for each char in new choice
** ChoicesList list with choices seen so far
** Variables Used:
** best_raw_choice_ best raw choice so far for current word
** Operation: This routine adds Choice to ChoicesList if the
** adjusted certainty for Choice is within a reasonable range
** of the best choice in ChoicesList. The ChoicesList
** list is kept in sorted order by rating. Duplicates are
** removed.
** Return: none
** Exceptions: none
** History: Wed May 15 09:57:19 1991, DSJ, Created.
*/
VIABLE_CHOICE NewChoice;
LIST ChoicesList;
LIST Choices;
FLOAT32 Threshold;
if (!keep_word_choices_)
return;
if (raw_choice) {
if (!best_raw_choice_)
best_raw_choice_ = NewViableChoice(WordChoice, AdjustFactor, Certainties);
else if (WordChoice.rating() < best_raw_choice_->Rating) {
if (ChoiceSameAs(WordChoice, best_raw_choice_))
FillViableChoice(WordChoice, AdjustFactor, Certainties, true,
best_raw_choice_);
else {
memfree(best_raw_choice_);
best_raw_choice_ =
NewViableChoice(WordChoice, AdjustFactor, Certainties);
}
}
if (!save_raw_choices) return;
ChoicesList = raw_choices_;
} else {
ChoicesList = best_choices_;
}
/* throw out obviously bad choices to save some work */
if (ChoicesList != NIL) {
Threshold = AmbigThreshold (BestFactor (ChoicesList), AdjustFactor);
if (Threshold > -stopper_ambiguity_threshold_offset)
Threshold = -stopper_ambiguity_threshold_offset;
if (WordChoice.certainty() - BestCertainty (ChoicesList) < Threshold)
return;
}
/* see if a choice with the same text string has already been found */
NewChoice = NULL;
Choices = ChoicesList;
iterate(Choices) {
if (ChoiceSameAs (WordChoice, (VIABLE_CHOICE) first_node (Choices))) {
if (WordChoice.rating() < BestRating (Choices)) {
NewChoice = (VIABLE_CHOICE) first_node (Choices);
} else {
return;
}
}
}
if (NewChoice) {
FillViableChoice(WordChoice, AdjustFactor, Certainties, true, NewChoice);
ChoicesList = delete_d(ChoicesList, NewChoice, is_same_node);
}
else {
NewChoice = NewViableChoice (WordChoice, AdjustFactor, Certainties);
}
ChoicesList = s_adjoin (ChoicesList, NewChoice, CmpChoiceRatings);
if (stopper_debug_level >= 2)
raw_choice ? PrintViableChoice (stderr, "New Raw Choice: ", NewChoice) :
PrintViableChoice (stderr, "New Word Choice: ", NewChoice);
if (count (ChoicesList) > tessedit_truncate_wordchoice_log) {
Choices =
(LIST) nth_cell (ChoicesList, tessedit_truncate_wordchoice_log);
destroy_nodes (rest (Choices), Efree);
set_rest(Choices, NIL);
}
// Update raw_choices_/best_choices_ pointer.
if (raw_choice) {
raw_choices_ = ChoicesList;
} else {
best_choices_ = ChoicesList;
}
} /* LogNewChoice */
/*---------------------------------------------------------------------------*/
int Dict::NoDangerousAmbig(WERD_CHOICE *best_choice,
DANGERR *fix_pt,
bool fix_replaceable,
BLOB_CHOICE_LIST_VECTOR *blob_choices,
bool *modified_blobs) {
if (stopper_debug_level > 2) {
tprintf("\nRunning NoDangerousAmbig() for %s\n",
best_choice->debug_string(getUnicharset()).string());
}
// Construct BLOB_CHOICE_LIST_VECTOR with ambiguities
// for each unichar id in BestChoice.
BLOB_CHOICE_LIST_VECTOR ambig_blob_choices;
int i;
bool modified_best_choice = false;
bool ambigs_found = false;
// For each position in best_choice:
// -- choose AMBIG_SPEC_LIST that corresponds to unichar_id at best_choice[i]
// -- initialize wrong_ngram with a single unichar_id at best_choice[i]
// -- look for ambiguities corresponding to wrong_ngram in the list while
// adding the following unichar_ids from best_choice to wrong_ngram
//
// Repeat the above procedure twice: first time look through
// ambigs to be replaced and replace all the ambiguities found;
// second time look through dangerous ambiguities and construct
// ambig_blob_choices with fake a blob choice for each ambiguity
// and pass them to dawg_permute_and_select() to search for
// ambiguous words in the dictionaries.
//
// Note that during the execution of the for loop (on the first pass)
// if replacements are made the length of best_choice might change.
for (int pass = 0; pass < 2; ++pass) {
bool replace = (pass == 0);
const UnicharAmbigsVector &table = replace ?
getUnicharAmbigs().replace_ambigs() : getUnicharAmbigs().dang_ambigs();
if (!replace) {
// Initialize ambig_blob_choices with lists containing a single
// unichar id for the correspoding position in best_choice.
// best_choice consisting from only the original letters will
// have a rating of 0.0.
for (i = 0; i < best_choice->length(); ++i) {
BLOB_CHOICE_LIST *lst = new BLOB_CHOICE_LIST();
BLOB_CHOICE_IT lst_it(lst);
lst_it.add_to_end(new BLOB_CHOICE(best_choice->unichar_id(i),
0.0, 0.0, 0, -1));
ambig_blob_choices.push_back(lst);
}
}
UNICHAR_ID wrong_ngram[MAX_AMBIG_SIZE + 1];
int wrong_ngram_index;
int next_index;
for (i = 0; i < best_choice->length(); ++i) {
UNICHAR_ID curr_unichar_id = best_choice->unichar_id(i);
if (stopper_debug_level > 2) {
tprintf("Looking for %s ngrams starting with %s:\n",
replace ? "replaceable" : "ambiguous",
getUnicharset().debug_str(curr_unichar_id).string());
}
wrong_ngram_index = 0;
wrong_ngram[wrong_ngram_index] = curr_unichar_id;
if (curr_unichar_id == INVALID_UNICHAR_ID ||
curr_unichar_id >= table.size() ||
table[curr_unichar_id] == NULL) {
continue; // there is no ambig spec for this unichar id
}
AmbigSpec_IT spec_it(table[curr_unichar_id]);
for (spec_it.mark_cycle_pt(); !spec_it.cycled_list();) {
const AmbigSpec *ambig_spec = spec_it.data();
wrong_ngram[wrong_ngram_index+1] = INVALID_UNICHAR_ID;
int compare = UnicharIdArrayUtils::compare(wrong_ngram,
ambig_spec->wrong_ngram);
if (stopper_debug_level > 2) {
tprintf("candidate ngram: ");
UnicharIdArrayUtils::print(wrong_ngram, getUnicharset());
tprintf("current ngram from spec: ");
UnicharIdArrayUtils::print(ambig_spec->wrong_ngram, getUnicharset());
tprintf("comparison result: %d\n", compare);
}
if (compare == 0) {
if (replace) {
if (stopper_debug_level > 2) {
tprintf("replace ambiguity with: ");
UnicharIdArrayUtils::print(
ambig_spec->correct_fragments, getUnicharset());
}
ReplaceAmbig(i, ambig_spec->wrong_ngram_size,
ambig_spec->correct_ngram_id,
best_choice, blob_choices, modified_blobs);
modified_best_choice = true;
} else if (i > 0 || ambig_spec->type != CASE_AMBIG) {
// We found dang ambig - update ambig_blob_choices.
if (stopper_debug_level > 2) {
tprintf("found ambiguity: ");
UnicharIdArrayUtils::print(
ambig_spec->correct_fragments, getUnicharset());
}
ambigs_found = true;
for (int tmp_index = 0; tmp_index <= wrong_ngram_index;
++tmp_index) {
// Add a blob choice for the corresponding fragment of the
// ambiguity. These fake blob choices are initialized with
// negative ratings (which are not possible for real blob
// choices), so that dawg_permute_and_select() considers any
// word not consisting of only the original letters a better
// choice and stops searching for alternatives once such a
// choice is found.
BLOB_CHOICE_IT bc_it(ambig_blob_choices[i+tmp_index]);
bc_it.add_to_end(new BLOB_CHOICE(
ambig_spec->correct_fragments[tmp_index], -1.0, 0.0, 0, -1));
}
}
spec_it.forward();
} else if (compare == -1) {
if (wrong_ngram_index+1 < ambig_spec->wrong_ngram_size &&
((next_index = wrong_ngram_index+1+i) < best_choice->length())) {
// Add the next unichar id to wrong_ngram and keep looking for
// more ambigs starting with curr_unichar_id in AMBIG_SPEC_LIST.
wrong_ngram[++wrong_ngram_index] =
best_choice->unichar_id(next_index);
} else {
break; // no more matching ambigs in this AMBIG_SPEC_LIST
}
} else {
spec_it.forward();
}
} // end searching AmbigSpec_LIST
} // end searching best_choice
} // end searching replace and dangerous ambigs
if (modified_best_choice) best_choice->populate_unichars(getUnicharset());
// If any ambiguities were found permute the constructed ambig_blob_choices
// to see if an alternative dictionary word can be found.
if (ambigs_found) {
if (stopper_debug_level > 2) {
tprintf("\nResulting ambig_blob_choices:\n");
for (i = 0; i < ambig_blob_choices.length(); ++i) {
print_ratings_list("", ambig_blob_choices.get(i), getUnicharset());
tprintf("\n");
}
}
WERD_CHOICE *alt_word = dawg_permute_and_select(ambig_blob_choices, 0.0);
ambigs_found = (alt_word->rating() < 0.0);
if (ambigs_found && stopper_debug_level >= 1) {
tprintf ("Stopper: Possible ambiguous word = %s\n",
alt_word->debug_string(getUnicharset()).string());
}
delete alt_word;
}
ambig_blob_choices.delete_data_pointers();
return !ambigs_found;
}
void Dict::EndDangerousAmbigs() {}
/*---------------------------------------------------------------------------*/
void Dict::SettupStopperPass1() {
/*
** Parameters: none
** Variables Used:
** reject_offset_ offset allowed before word is rejected
** Operation: This routine performs any settup of stopper variables
** that is needed in preparation for the first pass.
** Return: none
** Exceptions: none
** History: Mon Jun 3 12:32:00 1991, DSJ, Created.
*/
reject_offset_ = 0.0;
} /* SettupStopperPass1 */
/*---------------------------------------------------------------------------*/
void Dict::SettupStopperPass2() {
/*
** Parameters: none
** Variables Used:
** reject_offset_ offset allowed before word is rejected
** Operation: This routine performs any settup of stopper variables
** that is needed in preparation for the second pass.
** Return: none
** Exceptions: none
** History: Mon Jun 3 12:32:00 1991, DSJ, Created.
*/
reject_offset_ = stopper_phase2_certainty_rejection_offset;
} /* SettupStopperPass2 */
} // namespace tesseract
/**----------------------------------------------------------------------------
Private Code
----------------------------------------------------------------------------**/
/*---------------------------------------------------------------------------*/
void AddNewChunk(VIABLE_CHOICE Choice, int Blob) {
/*
** Parameters:
** Choice choice to add a new chunk to
** Blob index of blob being split
** Operation: This routine increments the chunk count of the character
** in Choice which corresponds to Blob.
** Return: none
** Exceptions: none
** History: Mon May 20 11:43:27 1991, DSJ, Created.
*/
int i, LastChunk;
for (i = 0, LastChunk = 0; i < Choice->Length; i++) {
LastChunk += Choice->Blob[i].NumChunks;
if (Blob < LastChunk) {
(Choice->Blob[i].NumChunks)++;
return;
}
}
mem_tidy (1);
cprintf ("AddNewChunk failed:Choice->Length=%d, LastChunk=%d, Blob=%d\n",
Choice->Length, LastChunk, Blob);
assert(FALSE); /* this should never get executed */
} /* AddNewChunk */
/*---------------------------------------------------------------------------*/
namespace tesseract {
// Replaces the corresponding wrong ngram in werd_choice with the correct one.
// We indicate that this newly inserted ngram unichar is composed from several
// fragments and modify the corresponding entries in blob_choices to contain
// fragments of the correct ngram unichar instead of the original unichars.
// Ratings and certainties of entries in blob_choices and werd_choice are
// unichaged. E.g. for werd_choice mystring'' and ambiguity ''->":
// werd_choice becomes mystring", first ' in blob_choices becomes |"|0|2,
// second one is set to |"|1|2.
void Dict::ReplaceAmbig(int wrong_ngram_begin_index, int wrong_ngram_size,
UNICHAR_ID correct_ngram_id, WERD_CHOICE *werd_choice,
BLOB_CHOICE_LIST_VECTOR *blob_choices,
bool *modified_blobs) {
int num_blobs_to_replace = 0;
int begin_blob_index = 0;
int i;
for (i = 0; i < wrong_ngram_begin_index + wrong_ngram_size; ++i) {
if (i >= wrong_ngram_begin_index) {
num_blobs_to_replace += werd_choice->fragment_length(i);
} else {
begin_blob_index += werd_choice->fragment_length(i);
}
}
BLOB_CHOICE_IT bit;
int temp_blob_index = begin_blob_index;
const char *temp_uch = NULL;
const char *correct_ngram_str =
getUnicharset().id_to_unichar(correct_ngram_id);
for (int replaced_count = 0; replaced_count < wrong_ngram_size;
++replaced_count) {
if (blob_choices != NULL) {
UNICHAR_ID uch_id = werd_choice->unichar_id(wrong_ngram_begin_index);
int fraglen = werd_choice->fragment_length(wrong_ngram_begin_index);
if (fraglen > 1) temp_uch = getUnicharset().id_to_unichar(uch_id);
for (i = 0; i < fraglen; ++i) {
if (fraglen > 1) {
STRING frag_str =
CHAR_FRAGMENT::to_string(temp_uch, i, fraglen);
getUnicharset().unichar_insert(frag_str.string());
uch_id = getUnicharset().unichar_to_id(frag_str.string());
}
bit.set_to_list(blob_choices->get(temp_blob_index));
STRING correct_frag_uch =
CHAR_FRAGMENT::to_string(correct_ngram_str,
temp_blob_index - begin_blob_index,
num_blobs_to_replace);
getUnicharset().unichar_insert(correct_frag_uch.string());
UNICHAR_ID correct_frag_uch_id =
getUnicharset().unichar_to_id(correct_frag_uch.string());
// Find the WERD_CHOICE corresponding to the original unichar in
// the list of blob choices, add the derived character fragment
// before it with the same rating and certainty.
for (bit.mark_cycle_pt(); !bit.cycled_list(); bit.forward()) {
if (bit.data()->unichar_id() == correct_frag_uch_id) {
break; // the unichar we want to insert is already there
}
if (bit.data()->unichar_id() == uch_id) {
bit.add_before_then_move(new BLOB_CHOICE(*(bit.data())));
bit.data()->set_unichar_id(correct_frag_uch_id);
if (modified_blobs != NULL) *modified_blobs = true;
break;
}
}
temp_blob_index++;
}
}
// Remove current unichar from werd_choice. On the last iteration
// set the correct replacement unichar instead of removing a unichar.
if (replaced_count + 1 == wrong_ngram_size) {
werd_choice->set_unichar_id(correct_ngram_id,
num_blobs_to_replace, 0.0, 0.0, wrong_ngram_begin_index);
} else {
werd_choice->remove_unichar_id(wrong_ngram_begin_index);
}
}
if (stopper_debug_level >= 1) {
tprintf("ReplaceAmbigs() modified werd_choice: %s\n",
werd_choice->debug_string(getUnicharset()).string());
werd_choice->print();
if (modified_blobs != NULL && *modified_blobs && blob_choices != NULL) {
tprintf("Modified blob_choices: ");
for (int i = 0; i < blob_choices->size(); ++i) {
print_ratings_list("\n", blob_choices->get(i), getUnicharset());
}
}
}
}
/*---------------------------------------------------------------------------*/
int Dict::ChoiceSameAs(const WERD_CHOICE &WordChoice,
VIABLE_CHOICE ViableChoice) {
/*
** Parameters:
** Choice choice to compare to ViableChoice
** ViableChoice viable choice to compare to Choice
** Operation: This routine compares the corresponding strings of
** Choice and ViableChoice and returns TRUE if they are the
** same, FALSE otherwise.
** Return: TRUE or FALSE.
** Exceptions: none
** History: Fri May 17 08:48:04 1991, DSJ, Created.
*/
return (StringSameAs(WordChoice, ViableChoice));
} /* ChoiceSameAs */
} // namespace tesseract
/*---------------------------------------------------------------------------*/
int CmpChoiceRatings(void *arg1, //VIABLE_CHOICE Choice1,
void *arg2) { //VIABLE_CHOICE Choice2)
/*
** Parameters:
** Choice1, Choice2 choices to compare ratings for
** Operation: Return -1 if the rating for Choice1 is less than the
** rating for Choice2, otherwise return (1).
** Return: -1 or 1
** Exceptions: none
** History: Wed May 15 13:02:37 1991, DSJ, Created.
*/
float R1, R2;
VIABLE_CHOICE Choice1 = (VIABLE_CHOICE) arg1;
VIABLE_CHOICE Choice2 = (VIABLE_CHOICE) arg2;
R1 = Choice1->Rating;
R2 = Choice2->Rating;
if (R1 < R2)
return (-1);
else
return (1);
} /* CmpChoiceRatings */
/*---------------------------------------------------------------------------*/
void ExpandChoice(VIABLE_CHOICE Choice, EXPANDED_CHOICE *ExpandedChoice) {
/*
** Parameters:
** Choice choice to be expanded
** ExpandedChoice place to put resulting expanded choice
** Operation: This routine expands Choice and places the results
** in ExpandedChoice. The primary function of expansion
** is to create an two arrays, one which holds the corresponding
** certainty for each chunk in Choice, and one which holds
** the class for each chunk.
** Return: none (results are placed in ExpandedChoice)
** Exceptions: none
** History: Fri May 31 15:21:57 1991, DSJ, Created.
*/
int i, j, Chunk;
ExpandedChoice->Choice = Choice;
for (i = 0, Chunk = 0; i < Choice->Length; i++)
for (j = 0; j < Choice->Blob[i].NumChunks; j++, Chunk++) {
ExpandedChoice->ChunkCertainty[Chunk] = Choice->Blob[i].Certainty;
ExpandedChoice->ChunkClass[Chunk] = Choice->Blob[i].Class;
}
} /* ExpandChoice */
/*---------------------------------------------------------------------------*/
int FreeBadChoice(void *item1, //VIABLE_CHOICE Choice,
void *item2) { //EXPANDED_CHOICE *BestChoice)
/*
** Parameters:
** Choice choice to be tested
** BestChoice best choice found
** Variables Used:
** stopper_ambiguity_threshold_gain
** stopper_ambiguity_threshold_offset
** Operation: If the certainty of any chunk in Choice is not ambiguous
** with the corresponding chunk in the best choice, free
** Choice and return TRUE. Otherwise, return FALSE.
** Return: TRUE or FALSE.
** Exceptions: none
** History: Wed May 15 13:20:26 1991, DSJ, Created.
*/
int i, j, Chunk;
FLOAT32 Threshold;
VIABLE_CHOICE Choice;
EXPANDED_CHOICE *BestChoice;
Choice = (VIABLE_CHOICE) item1;
BestChoice = (EXPANDED_CHOICE *) item2;
Threshold = AmbigThreshold (BestChoice->Choice->AdjustFactor,
Choice->AdjustFactor);
for (i = 0, Chunk = 0; i < Choice->Length; i++)
for (j = 0; j < Choice->Blob[i].NumChunks; j++, Chunk++)
if (Choice->Blob[i].Class != BestChoice->ChunkClass[Chunk] &&
Choice->Blob[i].Certainty - BestChoice->ChunkCertainty[Chunk] <
Threshold) {
memfree(Choice);
return (TRUE);
}
return (FALSE);
} /* FreeBadChoice */
/*---------------------------------------------------------------------------*/
namespace tesseract {
int Dict::LengthOfShortestAlphaRun(const WERD_CHOICE &WordChoice) {
/*
** Parameters:
** Word word to be tested
** Operation: Return the length of the shortest alpha run in Word.
** Return: Return the length of the shortest alpha run in Word.
** Exceptions: none
** History: Tue May 14 07:50:45 1991, DSJ, Created.
*/
register int Shortest = MAX_INT32;
register int Length;
int x;
int y;
for (x = 0; x < WordChoice.length(); ++x) {
if (getUnicharset().get_isalpha(WordChoice.unichar_id(x))) {
for (y = x + 1, Length = 1;
y < WordChoice.length() &&
getUnicharset().get_isalpha(WordChoice.unichar_id(y));
++y, ++Length);
if (Length < Shortest) {
Shortest = Length;
}
if (y == WordChoice.length()) {
break;
}
}
}
if (Shortest == MAX_INT32)
Shortest = 0;
return (Shortest);
} /* LengthOfShortestAlphaRun */
/*---------------------------------------------------------------------------*/
VIABLE_CHOICE Dict::NewViableChoice(const WERD_CHOICE &WordChoice,
FLOAT32 AdjustFactor,
const float Certainties[]) {
/*
** Parameters:
** Choice choice to be converted to a viable choice
** AdjustFactor factor used to adjust ratings for Choice
** Certainties certainty for each character in Choice
** Variables Used:
** current_segmentation segmentation corresponding to Choice
** Operation: Allocate a new viable choice data structure, copy
** Choice, Certainties, and current_segmentation_ into it,
** and return a pointer to it.
** Return: Ptr to new viable choice.
** Exceptions: none
** History: Thu May 16 15:28:29 1991, DSJ, Created.
*/
int Length = WordChoice.length();
assert (Length <= MAX_NUM_CHUNKS && Length > 0);
VIABLE_CHOICE NewChoice = (VIABLE_CHOICE) Emalloc (
sizeof (VIABLE_CHOICE_STRUCT) + (Length - 1) * sizeof (CHAR_CHOICE));
FillViableChoice(WordChoice, AdjustFactor, Certainties, false, NewChoice);
return (NewChoice);
} /* NewViableChoice */
/*---------------------------------------------------------------------------*/
void Dict::PrintViableChoice(FILE *File, const char *Label, VIABLE_CHOICE Choice) {
/*
** Parameters:
** File open text file to print Choice to
** Label text label to be printed with Choice
** Choice choice to be printed
** Operation: This routine dumps a text representation of the
** specified Choice to File.
** Return: none
** Exceptions: none
** History: Mon May 20 11:16:44 1991, DSJ, Created.
*/
int i, j;
fprintf (File, "%s", Label);
fprintf(File, "(R=%5.1f, C=%4.1f, F=%4.2f, Frag=%d) ",
Choice->Rating, Choice->Certainty,
Choice->AdjustFactor, Choice->ComposedFromCharFragments);
for (i = 0; i < Choice->Length; i++)
fprintf(File, "%s", getUnicharset().id_to_unichar(Choice->Blob[i].Class));
fprintf(File, "\n");
for (i = 0; i < Choice->Length; i++) {
fprintf(File, " %s", getUnicharset().id_to_unichar(Choice->Blob[i].Class));
for (j = 0; j < Choice->Blob[i].NumChunks - 1; j++)
fprintf(File, " ");
}
fprintf(File, "\n");
for (i = 0; i < Choice->Length; i++) {
for (j = 0; j < Choice->Blob[i].NumChunks; j++)
fprintf(File, "%3d ", (int) (Choice->Blob[i].Certainty * -10.0));
}
fprintf(File, "\n");
for (i = 0; i < Choice->Length; i++) {
for (j = 0; j < Choice->Blob[i].NumChunks; j++)
fprintf(File, "%3d ", Choice->Blob[i].NumChunks);
}
fprintf(File, "\n");
} /* PrintViableChoice */
/*---------------------------------------------------------------------------*/
void Dict::FillViableChoice(const WERD_CHOICE &WordChoice,
FLOAT32 AdjustFactor, const float Certainties[],
bool SameString, VIABLE_CHOICE ViableChoice) {
/*
** Parameters:
** WordChoice a choice with info that will be copied
** AdjustFactor factor used to adjust ratings for AChoice
** Certainties certainty for each character in AChoice
** SameString if true the string in the viable choice
** will not be changed
** ViableChoice existing viable choice to fill in
** Variables Used:
** current_segmentation_ segmentation for NewChoice
** Operation:
** Fill ViableChoice with information from AChoice,
** AdjustFactor, and Certainties.
** Return: none
** Exceptions: none
** History: Fri May 17 13:35:58 1991, DSJ, Created.
*/
CHAR_CHOICE *NewChar;
BLOB_WIDTH *BlobWidth;
int x;
ViableChoice->Rating = WordChoice.rating();
ViableChoice->Certainty = WordChoice.certainty();
ViableChoice->AdjustFactor = AdjustFactor;
ViableChoice->ComposedFromCharFragments = false;
if (!SameString) {
ViableChoice->Length = WordChoice.length();
}
for (x = 0,
NewChar = &(ViableChoice->Blob[0]),
BlobWidth = current_segmentation_;
x < WordChoice.length();
x++, NewChar++, Certainties++, BlobWidth++) {
if (!SameString) {
NewChar->Class = WordChoice.unichar_id(x);
}
NewChar->NumChunks = *BlobWidth;
NewChar->Certainty = *Certainties;
for (int i = 1; i < WordChoice.fragment_length(x); ++i) {
BlobWidth++;
assert(*BlobWidth > 0);
NewChar->NumChunks += *BlobWidth;
ViableChoice->ComposedFromCharFragments = true;
}
}
} /* FillViableChoice */
// Compares unichar ids in word_choice to those in viable_choice,
// returns true if they are the same, false otherwise.
bool Dict::StringSameAs(const WERD_CHOICE &WordChoice,
VIABLE_CHOICE ViableChoice) {
if (WordChoice.length() != ViableChoice->Length) {
return false;
}
int i;
CHAR_CHOICE *CharChoice;
for (i = 0, CharChoice = &(ViableChoice->Blob[0]);
i < ViableChoice->Length; CharChoice++, i++) {
if (CharChoice->Class != WordChoice.unichar_id(i)) {
return false;
}
}
return true;
}
/*---------------------------------------------------------------------------*/
int Dict::StringSameAs(const char *String,
const char *String_lengths,
VIABLE_CHOICE ViableChoice) {
/*
** Parameters:
** String string to compare to ViableChoice
** String_lengths lengths of unichars in String
** ViableChoice viable choice to compare to String
** Operation: This routine compares String to ViableChoice and
** returns TRUE if they are the same, FALSE otherwise.
** Return: TRUE or FALSE.
** Exceptions: none
** History: Fri May 17 08:48:04 1991, DSJ, Created.
*/
CHAR_CHOICE *Char;
int i;
int current_unichar_length;
for (Char = &(ViableChoice->Blob[0]), i = 0;
i < ViableChoice->Length;
String += *(String_lengths++), Char++, i++) {
current_unichar_length = strlen(getUnicharset().id_to_unichar(Char->Class));
if (current_unichar_length != *String_lengths ||
strncmp(String, getUnicharset().id_to_unichar(Char->Class),
current_unichar_length) != 0)
return (FALSE);
}
if (*String == 0)
return (TRUE);
else
return (FALSE);
} /* StringSameAs */
} // namespace tesseract
/*---------------------------------------------------------------------------*/
int UniformCertainties(const BLOB_CHOICE_LIST_VECTOR &Choices,
const WERD_CHOICE &BestChoice) {
/*
** Parameters:
** Choices choices for current segmentation
** BestChoice best choice for current segmentation
** Variables Used:
** stopper_allowable_character_badness
** max allowed certainty variation
** Operation: This routine returns TRUE if the certainty of the
** BestChoice word is within a reasonable range of the average
** certainties for the best choices for each character in
** the segmentation. This test is used to catch words in which
** one character is much worse than the other characters in
** the word (i.e. FALSE will be returned in that case).
** The algorithm computes the mean and std deviation of the
** certainties in the word with the worst certainty thrown out.
** Return: TRUE or FALSE.
** Exceptions: none
** History: Tue May 14 08:23:21 1991, DSJ, Created.
*/
float Certainty;
float WorstCertainty = MAX_FLOAT32;
float CertaintyThreshold;
FLOAT64 TotalCertainty;
FLOAT64 TotalCertaintySquared;
FLOAT64 Variance;
FLOAT32 Mean, StdDev;
int WordLength;
WordLength = Choices.length();
if (WordLength < 3)
return (TRUE);
TotalCertainty = TotalCertaintySquared = 0.0;
BLOB_CHOICE_IT BlobChoiceIt;
for (int i = 0; i < Choices.length(); ++i) {
BlobChoiceIt.set_to_list(Choices.get(i));
Certainty = BlobChoiceIt.data()->certainty();
TotalCertainty += Certainty;
TotalCertaintySquared += Certainty * Certainty;
if (Certainty < WorstCertainty)
WorstCertainty = Certainty;
}
/* subtract off worst certainty from statistics */
WordLength--;
TotalCertainty -= WorstCertainty;
TotalCertaintySquared -= WorstCertainty * WorstCertainty;
Mean = TotalCertainty / WordLength;
Variance = ((WordLength * TotalCertaintySquared -
TotalCertainty * TotalCertainty) /
(WordLength * (WordLength - 1)));
if (Variance < 0.0)
Variance = 0.0;
StdDev = sqrt (Variance);
CertaintyThreshold = Mean - stopper_allowable_character_badness * StdDev;
if (CertaintyThreshold > stopper_nondict_certainty_base)
CertaintyThreshold = stopper_nondict_certainty_base;
if (BestChoice.certainty() < CertaintyThreshold) {
if (stopper_debug_level >= 1)
cprintf("Stopper: Non-uniform certainty = %4.1f"
" (m=%4.1f, s=%4.1f, t=%4.1f)\n",
BestChoice.certainty(), Mean, StdDev, CertaintyThreshold);
return (FALSE);
} else {
return (TRUE);
}
} /* UniformCertainties */
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